A CMOS digitized salinity transducer with calibration circuits for monitoring salinity of ocean environment and aquaculture

In this paper, a CMOS digitized salinity transducer with calibration circuits for monitoring salinity of ocean environment and aquaculture is newly proposed. Another innovation is that the outputs of the proposed chip are directly digitized, they could be easily sent over a wide range of transmission media, such as PSN, radio, optical, IR, ultrasonic, and etc. Before performing the proposed calibration circuits, the maximum linear error is 8.02%. After calibration, the maximum linear error is reduced to 0.95%.The salinity ranges from 120 to 240 g/L, and the corresponding output frequency range is 515 to 546 kHz. The chip area is 1.058 × 1.058 mm². The proposed chip is suitable for devices of measuring salinity, such as device of detecting salinity of sea water.